How do I manually calibrate the BW GasAlert Extreme for Toxic Gases?

Post By: Dawn Smillie

In this short guide, we’ll walk you through the steps needed to manually calibrate your BW GasAlert Extreme single gas detector for toxic gases.

Note that the process may slightly differ for the oxygen version of the GasAlert Extreme.

In order to calibrate your unit, you’ll need the appropriate concentration of calibration gas, a length of tubing, a suitable regulator and the calibration cap which should be supplied with the gas monitor.  In this example we’re calibrating the Ammonia configuration of the BW GasAlert Extreme, so we’re using a calibration gas with the concentration 50ppm Ammonia in a balance of Nitrogen.

Before you begin calibration ensure the calibration cap is attached to one end of the tubing, and the other end of the tubing is attached securely to the regulator.  Screw the regulator on to the calibration cylinder. Do not connect the monitor to the calibration equipment just yet, as it will carry out a zero-calibration in fresh air before proceeding.

It’s important to ensure you are calibrating your gas detector in a safe area that is free of hazardous gas and in a fresh-air environment.

To switch the unit on hold down the green left-hand button and the unit will sound.  It will carry out some start-up checks and will display the current alarm levels and calibration due date.  Once this has completed the unit will display 0 ppm and is ready to be used.

In order to access the calibration menu, hold the down arrow and the blue circular button down simultaneously until the screen shows CAL. The unit will then AUTO-ZERO to ensure that the sensor is zeroed before calibration.  Once completed successfully the screen will then show Set - SPAN alongside the calibration gas concentration to be used.

In this case, as we’re using the 50ppm Ammonia gas, the screen should flash 50ppm. Press the blue circle to confirm this.  The unit is then ready to be calibrated. Secure the calibration cap on to the front of the monitor, over the sensor, and turn the regulator on to release the gas.

You will see that the sensors are starting to respond to the gas. The calibration process will take a few minutes to complete and this varies depending on the configuration.  Once a sufficient amount of gas has been detected, the unit will beep and the screen should then display ‘CAL DUE 180 Days’.  Turn off the regulator to stop the gas flow and remove the calibration cap.

After the calibration date has been confirmed as being 180 days, the preset low, high, STEL and TWA alarms can then be confirmed. Press the blue button to confirm each of these and return to the main screen for normal measurement mode.

If you'd like to see the video guide to this then view this on our YouTube Channel.